LibC: Implement wcsstr

2 files changed, 21 insertions, 0 deletions

diff --git a/Userland/Libraries/LibC/wchar.cpp b/Userland/Libraries/LibC/wchar.cpp
index 39eb3e8579..db255185af 100644
--- a/Userland/Libraries/LibC/wchar.cpp
+++ b/Userland/Libraries/LibC/wchar.cpp
@@ -355,4 +355,24 @@ wchar_t* wcspbrk(const wchar_t* wcs, const wchar_t* accept)
 
     return nullptr;
 }
+
+wchar_t* wcsstr(const wchar_t* haystack, const wchar_t* needle)
+{
+    size_t nlen = wcslen(needle);
+
+    if (nlen == 0)
+        return const_cast<wchar_t*>(haystack);
+
+    size_t hlen = wcslen(haystack);
+
+    while (hlen >= nlen) {
+        if (wcsncmp(haystack, needle, nlen) == 0)
+            return const_cast<wchar_t*>(haystack);
+
+        haystack++;
+        hlen--;
+    }
+
+    return nullptr;
+}
 }
diff --git a/Userland/Libraries/LibC/wchar.h b/Userland/Libraries/LibC/wchar.h
index 98c6824945..70ea7006a8 100644
--- a/Userland/Libraries/LibC/wchar.h
+++ b/Userland/Libraries/LibC/wchar.h
@@ -42,5 +42,6 @@ int wcscoll(const wchar_t*, const wchar_t*);
 int wctob(wint_t);
 int mbsinit(const mbstate_t*);
 wchar_t* wcspbrk(const wchar_t*, const wchar_t*);
+wchar_t* wcsstr(const wchar_t*, const wchar_t*);
 
 __END_DECLS